The invention relates to heat sinks and a method of attaching a heat sink to a device in order to allow the heat sink to draw heat away from the device. In particular, the invention relates to a heat sink which can be mounted and dismounted with minimum insertion force and which has a resilient holding member for securing the heat sink to the device, and to a method of mounting the heat sink.
It is commonly known in the art to connect a heat sink to various mechanical or electrical machines or devices in order to draw heat away from the machine or device. Many electronic devices fail if the temperature of the device rises above a particular temperature. Specifically, integrated circuits, capacitors, power amplifiers and other electronic components generate heat as electric current passes through the component. That heat must be dissipated in order to allow the device to operate normally.
In the case of electrical devices such as integrated circuits that are soldered to a printed circuit board, commonly known methods of connecting a heat sink to the device often causes stress on the package or on the leads connecting the package to the printed circuit board.
Commonly known heat sink devices in the art require a high insertion force, a mounting surface external to the device being cooled or must be mounted prior to soldering the package to the circuit board. Exemplary devices are shown and described in U.S. Pat. Nos. 4,872,089, 4,899,255, 4,972,294, 5,864,464, 5,875,097, and 5,886,870.
Accordingly, the invention provides a heat sink apparatus for drawing heat away from a device, and means for connecting the heat sink apparatus to a device with minimal insertion force. In particular, the means for connecting the heat sink apparatus to the device includes a mounting surface and a resilient holding member pivotally connected to the mounting surface for adjustable movement between a clamped position and a released position. In a preferred embodiment, the heat sink further includes a cam with a cam engagement surface, a removable user-operated cam actuator connected to the cam and a holding member which includes a pivot arm and spring clips. Rotational movement of the cam actuator is translated into horizontal movement of the holding member between the clamped and released positions to secure and release, respectively, the heat sink from the device.
The user of individual spring clips allows the heat sink to be mounted to multiple devices of different styles, shapes and at different locations along the mounting surface. Individual spring clips which do not engage a device pivotally rotate towards the mounting surface, but do not become compressed and do not contribute to the clamping of the heat sink.
The invention also provides a method of securing a heat sink apparatus to a device, the heat sink apparatus having a resilient holding member and a mounting surface, the method including placing the heat sink on the device so that the device is positioned between the mounting surface and the resilient holding member and rotating the cam actuator, thereby moving the resilient holding member between the released position and the clamped position to secure the heat sink to the device. In a preferred embodiment the heat sink includes cooling fins to provide a greater surface area to dissipate heat into the surrounding air.
In an alternative embodiment the cooling capability of the cooling fins on the heat sink could be supplemented with a power-actuated fan. Such power-actuated fans are well known in the art. In an additional alternative embodiment, a temperature monitor could be installed on the heat sink to monitor and report the operating temperature of the heat sink, thereby indicating the relative internal operating temperature of the device. Inclusion of such a monitor would ensure that the device was operating within safe operational temperature parameters and would allow for user intervention prior to device failure. Such temperature monitors are well known in the art.
It is a principal advantage of the invention to provide a heat sink that can be secured to a device either before or after soldering the device to a printed circuit board without stressing the device or device leads during installation.
It is another advantage of the invention to provide a heat sink that can be removed from a device after mounting the heat sink to the device on a printed circuit board without stressing the device or device leads during heat sink removal.
It is another advantage of the invention to provide a heat sink capable of simultaneously clamping a plurality of devices of varying styles to the heat sink.
It is another advantage of the invention to provide a heat sink that does not require front access to the device to mount the heat sink to the device.
It is yet another advantage of the invention to provide a heat sink that can be secured to the device without any additional hardware or external mounting surfaces.
Various other features and advantages of the invention are set forth in the following detailed description, drawings and claims.